Rotary fluid pump



March 17, 1953 E. l.. BAUGH ET Al. 2,631,540

ROTARY FLUID PUMP Filed Nov. 24, 1948 /hl VE/Y 7'0/95 EVA-'577' z. Baus/l ma Daoss D.`WALLAC Patented Mar. 17, 1953 ROTARY FLUID PUMP Everett L. Baugh and De Loss D. Wallace, Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application November 24, 1948, Serial N o. 61,826

(Cl. S-42) 9 Claims.

This invention relates to improvements in rosure provided by the pump itself. In the present invention the vanes moving along the cylinder wall in the region of the discharge port of the pump are urged against said wall at a greater pressure than the vanes moving along the cylinder wall in the region of the intake port.

This object is accomplished by providing the pump rotor with a fluid receiving space at .the

-inner end of each radial slot in which a vane is slidably supported and in addition providing a cylinder end wall with two separate, arcuate recesses, the one recess interconnecting the fluid receiving spaces of the several vanes as they move in the cylinder within the region of the intake port of the pump, the second recess interconnecting the fluid receiving spaces of the several slots the vanes in which are moving in the cylinder within the region of the discharge port of the pump. The said one recess is in communication with the discharge port of the pump so that fluid, delivered under pressure by the pump, is

directed against the inner ends of all of the vanes traversing the intake port region of the cylinder whereby' said vanes, moving outwardly of the rotor, are urged against the cylinder wall at pump, lluid delivery pressure. As the rotor of the pump continues to turn the spaces at the inner ends of the slots are successively moved out of communication with the said one arcuate recess and then, filled with uid, they are successively moved into .communication with the second recess adjacent the discharge port of the pump. As the vanes move through the region of said discharge port they are moved inwardly of the rotor and thus become reciprocating pistons exerting a pressure upon the fluid contained inthe respective slots of the vanes moving through this region and the uid accumulated in the communicating arcuate recess. yThe fluid trapped in the spaces and the communicating arcuate recess resists the inward movement of the vanes and consequently said vanes frictionally engage the cylinder wall at a .pressure greater than that at which the vanes 2 n moving through the intake port area engage the cylinder wall. In fact the trapped uid substantially prevents inward movement of the vanes and therefor provides too great an impedance to the safe and proper operation of the pump.

Therefore it is another object of the present invention to provide a predetermined fluid leak for the arcuate recess adjacent the discharge port of the pump and the vane slot spaces communicating therewith whereby a predetermined resistance to the inward movement of the vanes in this region may be provided. Such a controlled fluid leak is obtained by providing a predeterminately sized duct connecting the said arcuate recess adjacent the discharge port of the pump with said discharge port.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a plan view of the pump.

Fig. 2 is a sectional View taken along the line 2--2 of Fig. 1.

Fig. 3 is a fragmentary sectional view taken along the line 3-3 of Fig. 1.

Fig. 4 is a fragmentary sectional view taken along the line 4-4 of Fig. 1.

Fig. 5 is a view similar to Fig. 4, taken along the line 5-5 of Fig. 1.

Fig. 6 is a schematic view illustrating the rotor and cylinder with associated uid passages. y

As has previously been stated, the present invention relates to improvements in vane type, rotary fluid pumps. The pump illustrated in the accompanying drawings is designed to be applied to the starting motor for the engine of a motor vehicle, said pump being driven by said motor for the purpose of providing fluid pressure to operate top and window actuating devices.

Referring to the drawings, the pump is shown consisting of a base 20 which, when attached to the electric motor, forms one end housing there-4I of. A central opening in the base 20 has one end of the armature shaft 2l o f the electric motor journalled therein. A flat outer surface 22 is provided on the base 20, this surface of said base has a circular recess 23, eccentric to the shaft 2| as illustrated in Fig. 6. A cover cap 24 is secured to the base 20 by bolts 25 and bolts 26 pass through the cover cap 24 and the base 20 into the frame of the electric motor to secure the pump thereto. An annular groove in the at surface 22 of the base contains a sealing ring 21 which prevents the escape of iiuid betweenthe base and cover cap. The recess 23 closed at one end by the cover cap, forms the cylinder of the pump.

In this recess 23 or cylinder there is provided a disc shaped rotor 30 having a central opening into which the end of the shaft 2i extends, anchoringfrneans.beingl provided so.. that the rotor turns with the shaft. The eccentricity otv the shaft relatively to the recess or cylinder 23 and the diameter of the rotor 30 attached to the shaft are such that there is a sliding line contact or minimum space between said rotor andthe an-y nular wall of the recess or cylinder 23 .as desigfnated by the numeral 3l of Fig. 6.` The rotor 3S! thus forms a crescent shaped iiuiddisplacement chamber 32 within the cylinder 23 each pointed end of said chamber substantially"terminatingati'A` the line 3l. An end thrust bearing inthe form of a ball 33 is shown inthe present drawing as interposedbetweentheceyer cap..2.4. andthe end or considered necessary a... cylinder deviatingV from. the circular, shape may readily .be utilized in connection.. with the, features ofjthe. present inn vention. Also.. the: presentdrawings. show the shaft. supportingopening. in the. base.V 2d to.. be eccentric.. relatively t'o.tl'i\:.V cylinder recess.. To. simplify.Y machinery, thisopening maybe.` concentric.. with they cylinderrecess.. in which. case said. recess would not be the cylinder. directly. but wouldreceive,v awringf shaped. insert having an inner -bore eccentricfto the outer. peripheral'fsur--- face of the insert, saidinner bore forming.. the cylinder spaeeeccentric tothe shaft opening. In this instance the insert ringgrwith. its eccentric sperling` could be preformed andY made of any suitable-material as for instancecompressed and sintered powdered metal;

Referring particularly to Eig. 6, the rotor 30 is shown having-a; plurality of end to end openings 410, Me, 42,. 43,Y and 45 'arranged in; a circular row and equally spaced one from the other. Each opening; forms; theeinnerfterminus chamber'of a radial slot the outer end of. which terminates in the-outer peripheral surface of the rotor.v Each slot slidably supportsafiuiddisplacment vane. Openinggslot. 4c supports-vane 50.; 4I vane 5|, 42 vane 52, 43 vane 53, 44 Vane, 54and.45..vane.55.'

v In operation, the Jou-ten ends; of these fvanesvconstan-ily engage; thej wa-llV .of P the cylinder anddue tio; eceentrcty are.;V therefore; reciproca-ted the rotor slctsrasrthe rotorfturnsj. ara-so, de,-

signedthatwhen atv the position indicated"-v by numeral 311, the inne-r endof" the.; vane. extends within close, proximity of the: extreme; inner' portion; of the openi-ngoffitsv respective slot whilef in the; diametricallyy opposite position in the; cylinder, or@ where the V crescent shaped' spacer 32ais widest; the? inner. end: of. the; Vane is outside the contines,` of, thezend-v tov end opening of-I its. respective-slot.

The at surface of the -covercapengaging'the flat.v surface- 22"-of *the basehas apluralityI of separatel arcuatey recesses. Two of' these recesses 60j and @t are concentricV with the cylinder recess 231i and .are diametricallyfopposed. The recess Si! is? in.y direct communication with: one end portion of? the crescentshaped cylinder space-32 and has the'uidintake port 52 communicating therewith y wherebysuid; introduced'A through; port 62, enters the-arcuate recess*l liilarrd'A that portion ofthe crescent: shaped cylinder spacecommunicating therewith. Similarlyrecessii isgindirectcommunication with the opposite end portion ofthe crescent shaped cylinder space 32 and has the fluid discharge port 63 communicating therewith whereby uid displaced by the rotor vanes is forced under pressure from the pump.

The other two of the separate, oppositely disposed.. arcuate recess are. designated. by. the numerals Eiland 66'. While-the recessesi and 6| are concentric of the cylinder 23,` the recesses B5 and 66 are concentric of the rotor 30 and are spaced from the center of the rotor so that the several endatoiend openings 40 to 45 inclusive will register and communicate successively with the recesses 65 and- 65 as therotor turns. The arcuate recesses gandfinzcaplf are of such length respectively that, as shown, three end to end openings 40 to '!i5may-'regi'stcrr.with each recess at one time. Fig.` @illustrates this clearly by showing that end to end openings 4|, 42; and 43 may register and communicate with ther arcuate recess 65 vas the respectivetvaIIeS-5'l'y 52 and 53L move in; thc'ercgion o fj the'iintake recess Scand likewise end tofend.

openings.44" 4 andli)4 register" recess 66` as the respective-vanes .54; 55and` 5move inf. the regiorroi'the;dischargemrecessl 61: In` each instance.asthetleadingfend to end lopening approachesftheendo arespective recess 65 orfBE to break'communication'tlierewtln the Vsecond- -following end to end opening .is completingv communic'ation with recess 65`-ori66respectively# In the meantime the intermediate" end tc-endt openingismidway between-:the ends-'ofi' atrespe'cti've recess 65 011.662.

Afluid receiving recess 1B isprovided inw the "cover cap 24;"the openfend of'isaidrecess'being closed byia screw plu'gjlf.; AsshownfiwFig; 3, recess l5 comprises two.' portions of" diierent'diameters. forming. an innen;k annular'shoulder'cr ledge -2upon vwhich thevalve"13is yie'ld'ably urged by. a" springy 14,;interposed`between the valve and'screw plug. This valve .T31divides'recess, l' into. two chambers'lB`- andldnormally not.r in. communication with. each' other.

The chamber VT5' has. theorie endorthe' recess. cutting; thereinto Sothatsaid' chamber '1.5.` is constantly in.v communication withthe recess. alifintlo, which the. ntakeport 'S2 Opens? The chamber TSjis cutintojby one 'end' oi recess 6| thereby placing; saidl chamber '16j in constant communicationA with the recess El' connectedito the, discharge. Hort. 6.3,of the. pump.. Thus. as the rotating. rotor. of-.nthe pump builds, un iluid pressure. ini ther'discharge, recessl'. which pressure is directed. into; their chamber; 15;'.

pressure. does not. exceed* agpredetermined. value vaLve 1,3;'willl be. held; union. theseat. Vci; ledge. 'i2 by. .Sprne;1 4.; howevenii said. fluid. pressure; becomes.. excessive, then valve. 1.3 Twill; belifted.' and chamber 15' willibe opened. to chamber. 76;, there- .by permitting the fluid. under pressure in chamber ljto be dissipated through chamber 7.5."into the. intake recess 5,5.

Chamber.. 76.. is also inV communication with the arcuate recessbiy means of duct 8a. which is of such size as. to. offer. littleor. no restriction ate.; recess;V 6.55am; thereby; eommimicates .there- As long; as thisl with. I'his urges these vanes into sealingA engagement with the cylinder wall as they slide along its surface within' the region of the intake recess 60. As soon as an end to end opening of a slot reaches the end of the arcuate recess 55, for instance in Fig. 6, as soon as end to end opening 43 is moved counterclockwise out of communication with the recess 65, duid is trapped in said opening while it is moving toward the diametrically opposite, arcuate recess 56. However, as soon as 'the opening, for instance opening 43, is moved to communicate with said recess 65 the fluid in opening 43 will enter said recess 66 which, after a few. revolutions of the pump, will become completely lled. Thus eventually rall end to end openings communicating with the recess 65 as well as said recess will be filled with fluid.

By referring to Fig. 6 it may be seen that as the vanes are moved counterclockwise from the line 3l between the rotor and cylinder wall to the diametrically opposite side of the cylinder, they move radially outward relatively to 'the rotor. Likewise as said vanes are moved in the same direction for the remaining half of a roltation of the rotor, they will be moved radially inward relatively to the rotor. Thus in Fig. 6 the vanes 54, 55 and 59 become reciprocating pistons moving inwardly to exert a pressure upon the uid in the end to end openings of their respective slots as well as upon the fluid within the communicating arcuate recess 6E. Where only internal leakage in the pump is depended upon to relieve the uid pressure within the arcuate recess 65 and the end to end openings Vcommunicating therewith, excessive resistance to the inward thrust of the several vanes will create too great a frictional engagement of rsaid vanes with the cylinder wall and thus proper operation of the pump is seriously affected and breakage possible.

In order to avoid this undesirable condition the present pump is provided with a duct 9i) of Ypredetermined fluid flow capacity, said duct acting as a uid pressure exhaust passage connecting the arcuate recess 65 with the fluid chamber 16. Duct 90 thus restricts fluid discharge from the recess 56 influenced by the inwardly moving vanes, to any desirable degree so that any desirable fluid pressure may be maintained within the recess 66 and its communicating end to end openings thereby resisting the inward movement of said vanes by the cylinder wall to any-desirable degree.

From' the aforegoing it may be seen that the improved pump of the present inventionentirely eliminates the use of springs for urging" the vanes into cylinder wall engagement and in lieu thereof uses the fluid at pump delivery pressure #to urge those vanes against the 'cylinder wall thatv are passing through the region of iiuid intake. While the vanes pass through the region of uid discharge, the vanes themselves perform two functions. They not only displace the fluid within the cylinder but also act as reciprocative pistons tending to compress the uid at their inner ends, said compressed fluid being exhausted from behind the vanes predeterminately so that a desired resistance to inward movement of the vanes is established and good sealing contact of the vanes with the cylinder wall main- "tained especially at the discharge region of the pump.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What'is claimed is as follows:

1. A rotary pump comprising a housing having a circular recess providing a cylinder; a drive shaft rotatably supported by the housing and eX- tending eccentrically into said recess; a cover cap for the housing forming a closure for said cylinder; a disc-shaped rotor eccentrically supported within the cylinder by said drive shaft and forming a crescent shaped uid displacement chamber within the cylinder; two diametrically opposite, segmental recesses in the cover cap, one forming a iiuid intake port, the other a fluid discharge port; equally spaced, radial slots in the peripheral wall of the rotor; a vane slidably supported in each slot respectively; a chamber in said cover cap; a spring loaded valve in said chamber, dividing it into two separate compartments; means connecting the one compartment with the intake port; means connecting the other compartment with the discharge port; two separate arcuate channels in the cover cap, each being adjacent a segmental recess, the one channel connecting together only the slots of the respective vanes as they traverse the intake port, said one channel being in constant communication with the compartment connected to the discharge port, the other channel connecting together only the slots of the respective vanes as they traverse the discharge port; and a fluid flow restricting duct connecting said other channel with the compartment communicating with the discharge port.

2. A rotary pump comprising a housing having a circular recess providing a cylinder; a drive shaft journalled in the housing and extending into said cylinder eccentric thereof; a cover cap for the housing closing said cylinder; a circular rotor eccentrically supported within the cylinder by said drive shaft and forming a uid displacement chamber therein; fluid intake and discharge ports in the cap, communicating with the displacement chamber; a chamber in the cap; a spring loaded valve in said chamber dividing it into two separate compartments, the one compartment on the spring engaged side of the valve being in communication with the intake port, the other with the discharge port; radial slots in the outer, peripheral wall of the rotor; a vane slidably supported in each slot respectively, the inner end of each slot being enlarged; two diametrically opposite, separate arcuate recesses in the cap capable of communicating with the enlarged ends of the slots, one of said recesses being connected to the said other compartment communicating with the discharge port and interconnecting several slots in the rotor only as the vanes of these several slots traverse the intake port, the other of said recesses interconnecting several slots in the rotor only as the vanes in said several slots traverse the discharge port; and a fluid now controlling duct connecting said other recess with the compartment communicating with the discharge port, said duct providing a substantially constant, predetermined restriction to the ow of fluid from said other recess under the displacement effect of the inwardly moving vanes.

3. A rotary pump consisting of a housing having recesses providing a cylinder having an annular wall and a fluid chamber divided into two compartments; separate ducts connecting said cylinder and the respective compartments, one

duct forming a fluid intake port, the other a iiuid discharge port for the cylinder; a drive shaft; a fluid displacement member rotatably supported acercan.

byy sai i;drive, shaft eccentrically within; the.V cylinder, said member having a plurality, of 'radial slots; a vane slidably. supported. ineach slot. and being.' adapted 13o-engage. the annular. Wall ofthe cylinder;vr auid passage providing communication1 betweenV the one compartmentr of. the. fluid chamber and the inner ends` of only. thoseradial grooves in= the displacementlmember whose vvanos aretraversing theintake port regionofl the cylinder; a-.second fluid passage providing communicationbetween. the inner endsf of only, those slots Whose vanos are traversing the. discharge port area of ,the.cylinder;. and aiiuidpassage having a flowrestricting portion, saidv passage connecting said..second passage.withwthe saidv one compartmentcf theuidchamber..

4.,. A. rotary pump consisting ofi a housinghaving recessesproviding a. cylinder having an an'- nular Wall, a fluid chamber divided'into' two' normally non.-communicating'k compartments and ducts connectingF the cylinder With. the; respective compartments of said chamber, oneduct forming a'uid intake port, the other a fluid discharge port for said. cylinder; a drive shaft;I a rotary piston in the cylinder attachedit'o thedriveshaft eccentrically ofthe cylinder, saidy piston having a'pluralityof radial slots, the inner end of each terminating` in a separate enlargedtransverse opening in` thel piston, said transverse openings being' arranged" in acircular row concentricV of the piston;v a vane inl each piston slot, slidable therein for engagement with theannu'lar cylinder Wall eccentric tothe'piston-tvvo separate, arcuate groovesl in thel housing, concentric off the piston, one groove being adjacent the intake port and interconnecting` the enlarged openings of only those grooves thelvanes-in which are traversing the intake port area ofthe cylinder, the second groove being adjacent thedischargeport and interconnecting' the enlarged` openings of only those grooves thevanes in Which'l are traversing the dischargeport area of the cylinder; a fluidpassage connecting theonecompartment of the .iiuid chamber with the one groove; and auid passage of predetermined fluid restrictingv characteristics connecting the said oneicompartment-of thezfluid chamber with the second. groove.

5a A rotary pump consisting ot ahousingrotatably supporting a drive shaftand having recesses providing a' cylinder and aV tvvov compartment iiuid chamber and separate ducts connecting said cylinder and the respective compartmentsof the chamber,` one ductforrning a uid intake port, the other a vfluid discharge portorthecylinder; aiiuidV displacement member rotatably supportedby'the driveshaft' eccentrically- Within .the cylinder; said member having' aiplurality?.v of radial slots; a vane slidably. supported in each.- sl'ot` and being' adapted toV engage the Wallof. the cylinder; two separate, arcuate-grooves` inV the' housing, one

groove connected to one compartment of the fluid chamber and operative to. interconnect hydrauli/callyY only the'y inner ends' oi those-vanos` in' the iiuid displacement member traversing the intake port area ofthe piston, the second' groove,- connected to thesaid one compartmentv oft-he fluid chamber by a duct of' predetermined fluid restricting characteristics, beingoperative to interconnect hydraulically, th'einner. endsoflthose vanos traversing the' discharge? portr area. ofv the cylinder.

6.` A; rot'ary'pump consisting or a'housing r0- tatabl'ysupporting a .drive shaft' and: having reoessesy providing aL cy li"nder a4 fluid chamber. divided. into tvvoV compartments andseparatey ducts connecting thev cylinder.. with the respective compartments of said chamber, one ductlforming ailuid intakeport, the other a fluid .discharge port for saidcylinderiarotaryT piston. attached to the drive. shaft` andeccentric' ofi vthe cylinder;l said piston, having. a. plurality l of. radial slots a .vane slidably supported ineach slot. and shorter than the` depthof` the. slot, said vanesslid'ably engaging the cylindery Wall; two, separate 'ud' channelsin the housing each operative t'o communicate with` and interconnect. certain of. said'vane supporting slots,V the..one channel. with.. no more than one-halt ofA sad-y slotsin; the. pistony concurrently., the secondgchannelwthno moretharrthe other half of said slots concurrently; and,V separate fluid passages connectingeach channerwith onecompartment of the fluid` Chambon one of said passages` having greater`V iluid restricting characteristicsfthanithe other.

7-. A device-in accordance Withzclaim. Binewhich the iiuid chamber.- isdivided into tvvo.A compartments by a spring loaded valve. operative in responseT to Vduid, pressure inv` the compartment communicating` with the dischargeport,4 for connecting'the. said discharge` port. withthe compartment communicating With'theintake port.

8. A- device inaccordancev with claim .47 inwhich thefiuid chamber isldivided into two compartments by a normallyl closed, spring loaded-.valve operative by fluidV pressure in said one compartment, with which the dischargeport communicates, for connecting both compartmentsthe iuid passages communicating with both arcuate groovesf being connected to said. one compartment.

9. A rotary pumpfconsisting of-v a. housing rotatably supporting: a'. driveA shaft and" havingY recesses providing' a cylinderand-fluidi chamber means providing two compartments and separate ducts connecting saidwcylinder andthe respective compartments'of the chamber means, one duct-forming afluidzintakeporuthe other afluid discharge port-for: the-cylinder; a fluid displacementmember rotatably supported bythe. drive shaft eccentrically.A within'the cylinder, said' member'having a plurality of radial slots; a'vane slidably supported-.ineachslot andfbeing; adapted to engagev the' wall of: the cylinder; tvvoy separate. arcuatexgroovesin thehousing; one groove Iconnected. to one:T compartment of the. fluid chamber meansandop'eraztivetointercormecthydraulically only the inner ends of those vanes'in. theifiuid displacementxmember: traversingv the. intakeV port area4 o" thezpiston;A second: groove,v connected to thea-said one compartment-of thefluid chamber means by a1ducti of' predetermined uid. restrictingcharacteristics, being; operative tol inteconne'ctv hydraulically; the.i inner' ends ofY those vanes traversing.the discharge port' area` of' the cylinder.

EVEREFITL. BAUGH'.. DE LOSS D.y WAlLACE,

REFERENCE-S CITED The following references' are *ofiv record inA the le of'thispatent? UNITED STATES' PATENTS NumberV Name Date 226,773 Newcomb Apr. 20,1880 2,411,602.. 'llweedale... ..,Noy; 26,1946 

